In recent years, mobile wireless communications have become increasingly popular. Initial implementations of mobile wireless communications, for example in the form of cellular telephone networks, supported circuit switched voice communication services. The carriers developed short message service (SMS) technology to provide text and/or e-mail communications via the wireless networks. Today wireless carriers also offer packet data communication services to their mobile customers. The deployment of broadband packet-based wireless networks allows the carriers and other service providers to offer a variety of new services via Multimedia Messaging Service (MMS) technologies, which enable users of mobile devices to send and receive multimedia content, such as text, graphics, digital photographs, audio files and video clips, via non-real-time transmission.
Prepaid communications services, in which a customer or subscriber prepays for usage of a communications system, have become increasingly popular. Such services now encompass an array of mobile wireless communications. In an example of a prepaid wireless service, the customer may purchase blocks of time for making voice telephone calls via a cellular telephone network. Upon connecting to the wireless communications network, the customer account is authorized and authenticated, and the network allows a call to proceed. The network monitors the customer's usage time and decrements from the customer's account. If the account becomes depleted, the system can either prompt the customer to purchase more time, or the system can terminate the call. The network blocks further calls on the account, until or unless the customer prepays additional funds into the account (replenishes the account) to buy more air time. Prepaid wireless communications system enable the customer to budget an amount of airtime that will be used during a certain period of time, and to insure that the budget will not be exceeded unless the customer purchases more airtime. The wireless service provider likes this type of service, because the carrier receives payment in advance and need not run the risk that the customer will default on a bill, as sometimes happens with postpay type billing services.
Service providers have extended their prepaid offerings to encompass various wireless data services, including SMS and MMS type messaging services. A messaging service (e.g., Short Message Service or Multimedia Message Service) uses one or more “message centers” that are responsible for receiving and forwarding messages addressed to its subscribers to the addressed subscribers' stations, and responsible for receiving and forwarding messages originated by its subscribers to equipment of the addressed recipients of those messages. The support of real-time prepaid charging for message services may be accomplished through a combination of message center policy and signaling interfaces (to be referred to as the prepaid accounting interfaces) between the message centers and the prepaid servers. These signaling interfaces support a BalanceCheck transaction, which allows a message center to check the remaining balance in a prepaid subscriber's account. The signaling interfaces also support a DebitAccount transaction that allows a message center to request the prepaid server to apply a charge against the subscriber's account for a message the subscriber has sent or received.
Typically, these transactions identify the prepaid subscriber that has sent or will receive a message, but they do not identify the other participant (destination or source). A message center policy controls the interaction between the message center's use of the prepaid accounting interfaces and the message center's processing of messages sent by or addressed to a prepaid subscriber. The policy reflects a service provider's decision regarding the tradeoff between the service provider's desire to offer high performance (low latency) messaging services and to avoid revenue loss that would occur if messages were accepted from or delivered to subscriber's whose prepaid account is depleted.
For example, assume that the service provider places a greater emphasis on the avoidance of revenue loss. The message center policy may dictate that a subscriber-initiated message is not processed until after a DebitAccount has been sent and a response received indicating that the subscriber has been charged. The message center policy may dictate that it perform a BalanceCheck for a prepaid subscriber before processing a message addressed to that subscriber. The message intended for the subscriber would be forwarded to the mobile station of the prepaid subscriber only if the response from the prepaid server indicates an account balance is high enough. Otherwise, the message center might either discard the message or store the inbound message for later delivery (once the subscriber's account had been replenished).
On the other hand, if a service provider places a greater emphasis on performance, the policy may dictate that messages are normally processed before the DebitAccount is sent, with the message center only delaying message processing. In this case, the message center might only perform a BalanceCheck for a prepaid subscriber if the subscriber's account had been marked as “blocked” because response to a previous DebitAccount message for the subscriber had indicated that the subscriber's account balance was too low to pay for a message. In this second case, the policy might dictate that the subscriber's account be “unblocked” and normal processing be resumed once a BalanceCheck indicates that the subscriber's account balance has been replenished so that it is no longer too low to pay for a message. Until then, the policy might dictate that the message center discard subscriber initialed messages, whereas messages addressed to the subscriber would either be discarded or stored for some period to allow for later delivery to the subscriber (once the subscriber's account had been replenished and thus “unblocked”).
A range of policies are possible between these extremes, reflecting different carrier preferences regarding the tradeoff between performance and the avoidance of revenue loss. However, since, signaling on the prepaid charging interface does not identify the destinations (respectively, the source) to which a message is being sent (response from which this message is received), a service provider cannot use this signaling to build services offering subscribers limited or unlimited free messaging, for messages sent to select destinations or received from select sources.
Signaling enhancements would be desirable to allow a service provider to offer a variety of free messaging options to its subscribers (or to a select group of its subscribers). Examples of desirable free service options include (but are by no means be limited to) free messaging for messages sent to or received from the service provider's other subscribers, messages sent to or received from destinations or sources from the subscriber's own country (or state or city/county) and/or messages sent to or received from destinations or sources on a list provided by the subscriber (e.g., a list of select friends, family members, or close business associates).
For some applications, it may also be desirable to allow message centers to recognize when the prepaid server has determined that a message should be treated as free. This would allow service providers to optimize message center policy, so that message centers can interact more intelligently with prepaid services that offer various specialized messaging plans.